Automattic / jetpack

			// If it's an associative array, use the keys to check that the value is among those admitted.

			$enum = ( count( array_filter( array_keys( $args['enum'] ), 'is_string' ) ) > 0 ) ? array_keys( $args['enum'] ) : $args['enum'];

			if ( ! in_array( $value, $enum ) ) {

				return new WP_Error(

					'invalid_param_value',

					sprintf(

					/* Translators: first variable is the parameter passed to endpoint that holds the list item, the second is a list of admitted values. */

						esc_html__( '%1$s must be one of %2$s', 'jetpack' ),

		$modules = Jetpack::get_available_modules();

		if ( count( array_intersect( $value, $modules ) ) != count( $value ) ) {

			return new WP_Error( 'invalid_param_value', sprintf( esc_html__( '%s must be a list of valid modules', 'jetpack' ), $param ) );

		}

		return true;

	}

		$sharer   = new Sharing_Service();

		$services = array_keys( $sharer->get_all_services() );

		if ( ! empty( $value ) && ! in_array( $value, $services ) ) {

			return new WP_Error( 'invalid_param', sprintf( esc_html__( '%s is not a registered custom sharing service.', 'jetpack' ), $param ) );

		}

		return true;

	}

							$allowed_object_types = array_keys( self::get_allowed_object_types() );

							if ( ! in_array( $value, $allowed_object_types, true ) ) {

								return new WP_Error(

									'rest_invalid_param',

									sprintf(

										/* translators: %s: comma-separated list of allowed object types */

										__( 'The object_type argument should be one of %s', 'jetpack' ),

										implode( ', ', $allowed_object_types )

									),

									array( 'status' => 400 )

								);

							}

							return true;

						},